Commentary & Perspective

Commentary & Perspective on
"Shoulder Arthroplasty in Patients with a Prior Anterior Shoulder Dislocation: Results of a Multicenter Study"
by Jean Matsoukis, MD, et al.

Commentary & Perspective by
Robin R. Richards, MD, FRCSC*,
Division of Orthopaedic Surgery, Sunnybrook and Women's College Health Sciences Centre, Toronto, Ontario, Canada

The study by Matsoukis et al. focuses on a cohort of patients whose specific subtype of glenohumeral osteoarthropathy ("dislocation" and "capsulorrhaphy" arthropathy) has heretofore received minimal scrutiny in the literature^1,2. The cohort of patients was assembled from a group of 1542 primary shoulder arthroplasties performed over a seven-year period of time. Notably, the patients in the Matsoukis review were culled from the practices of fifty-seven surgeons in nine different countries. Approximately one-half of the cohort had undergone prior surgery to stabilize the glenohumeral joint, and the remaining twenty-eight shoulders had not. The results of shoulder arthroplasty for the latter group have not previously been reported. This fact demonstrates the great value of multisurgeon/multicenter studies in assembling large patient groups so that relatively uncommon problems, such as that studied by Matsoukis et al., can receive the scrutiny they deserve.

In the patients who had had previous surgery, the mean delay from the first operation for treatment of the instability to the shoulder arthroplasty was 20.1 years. In the patients who had not had prior surgery, the mean time from the first instability episode to the shoulder arthroplasty was 18.6 years. Most patients had concentric osteoarthritis although nine of the fifty-five patients had posterior subluxation of the humeral head. Only one patient had glenoid retroversion. The humeral arthroplasty was positioned anatomically in fifty-three shoulders and intentionally retroverted in two. The patients were evaluated postoperatively with an age and gender-adjusted Constant score. The mean follow-up was forty-five months (range, twenty-four to eighty-seven months). There were four cases of postoperative anterior glenohumeral instability, one of which occurred following intentional placement of the humerus in excessive retroversion. In all, there were ten complications. Six patients required further surgery.

Thirty-nine shoulders underwent glenoid resurfacing, and, of these, twenty-one were found to have periprosthetic radiolucent lines, five of which were progressive. Although no significant differences were found in any of the preoperative factors between the patients undergoing total shoulder arthroplasty and those treated with hemiarthroplasty, patients treated with total shoulder arthroplasty demonstrated a better mean activity score, a better adjusted Constant score, and improvement in active external rotation, postoperatively.

The results of operative treatment were, in general, quite satisfactory with an increase in the mean Constant score from 30.8 to 65.8 postoperatively. Previous reports in the literature have been limited to patients in whom instability had been previously treated surgically. The authors found that the presence of a rotator cuff tear was a negative prognosticator for shoulder function preoperatively and postoperatively but chose not to repair the tears if they were present. The authors were concerned that such repairs might cause stiffness, and evidently they are correct in this regard since the patients with unrepaired rotator cuff tears had comparable gains in outcome parameters and even more of a gain in active anterior elevation when compared with patients with intact rotator cuffs!

As other authors have found when treating primary osteoarthritis, the results of total shoulder arthroplasty were better than those of hemiarthroplasty³. Evidently, total shoulder arthroplasty produces superior results in most patients, although caution is required in patients with rotator cuff tears. Matsoukis et al. found that two of the three cases of glenoid loosening occurred in patients with a deficient rotator cuff, and they advise, based on their experience, that glenoid resurfacing should be avoided in patients with dislocation-induced arthritis and a deficient rotator cuff.

The Matsoukis study fails to support the classic description of an association between capsulorraphy-induced arthropathy and posterior subluxation and posterior glenoid wear. In fact, there was no difference in glenoid morphology or the prevalence of posterior subluxation between the shoulders treated previously with stabilizing surgery and those treated nonoperatively. On the basis of their data, the authors correctly, in my view, question the existence of the condition termed "capsulorraphy arthropathy." In fact, in their larger series, the authors have observed that up to 19% of patients with primary osteoarthritis may have posterior glenoid erosion⁴. Matsoukis et al. concede that their study is relatively short-term and that patient-based functional outcome measures were not used. Nevertheless, the study contains important information that will be useful to clinicians. Shoulder arthroplasty is effective in treating patients with osteoarthropathy following previous anterior instability regardless of whether or not the patient has had prior surgery. Furthermore, the authors' careful clinical review has called into question the popular concept of the pathoanatomy of capsulorrhaphy arthropathy, which has previously been widely accepted. This reviewer compliments Matsoukis and coworkers for bringing forward this valuable information.

*The author did not receive grants or outside funding in support of the research or preparation of this manuscript. He did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the author is affiliated or associated.

References

1. Neer CS 2nd, Watson KC, Stanton FJ. Recent experience in total shoulder replacement. J Bone Joint Surg Am. 1982;64:319-37.
2. Samilson RL, Prieto V. Dislocation arthropathy of the shoulder. J Bone Joint Surg Am. 1983;65:456-60.
3. Gartsman GM, Roddey TS, Hammerman SM. Shoulder arthroplasty with or without resurfacing of the glenoid in patients who have osteoarthritis. J Bone Joint Surg Am. 2000;82:26-34.
4. Walch G, Boileau P. Presentation of the multicentric study. In: Walch G, Boileau P, Molé D, editors. 2000 prosthèses d'epaule…recul de 2 á 10 ans. Paris: Sauramps Medical; 2001. p 13-20.